Roof decking generally comprises sheets of plywood, oriented strand board (OSB) or the like which are nailed or otherwise fastened to structural members i.e., rafters, defining the roof of a building. The decking forms the substrate onto which water-shedding materials, such as tar paper and shingles, are attached to complete the roof.
This structure provides rather little insulation, the insulative properties of the roof structure being limited to that of the materials themselves. Efforts to improve the insulative solar or heat emitting properties of the roof have been limited to insulative materials applied to the exterior side of the roof decking under the water-shedding materials, or insulative or reflective materials hung below the decking layer.